1. Field of Invention
The present invention relates to a power controller and, more particularly, to a hybrid 4-in-1 power controller chip for a PC mainboard integrating a synchronous buck switching regulator, a standard buck switching regulator, a linear controller and a linear regulator.
2. Description of Related Art
Power supplies are usually divided into two basic types; linear regulator and switching regulator. Linear regulators have the merits of small ripple, fast dynamic response and little interference. However, the low conversion efficiency of linear regulators is not suitable for high-power applications such as a high-performance central processing unit (CPU) whose power consumption exceeds 30 watts. To efficiently convert 5 volts from the power supply of a computer to 1.3-3.5 volts as the power supply for a CPU, a buck switching regulator is adopted because of its greatly improved DC-DC conversion efficiency. However, the ripple, dynamic response, and noise of the switching regulator cannot compare with the linear regulator.
The whole switching regulator system can be integrated into a small space via a high-density package. This type of module can greatly decrease the system area and weight, but the cost is high. It has been suggested that switching frequency and output voltage can be adjusted according to the specific tasks which the CPU is processing, but its large output ripple cannot meet the VRM8.4 design guidelines established by Intel for the power supplies of the newest Pentium III CPUs. In addition to the switching regulator for the CPU, there are other switching and linear regulators on the PC mainboard for other circuits.
With the development of the VLSI process, it is now possible to integrate all of the controllers of the switching and linear regulators into one chip, which can meet the demand of increased integration and reduced costs.
To achieve the above-mentioned objects and advantages, the present invention provides a new hybrid 4-in-1 power controller chip for a PC mainboard which integrates a synchronous buck switching regulator to supply the CPU core voltage, a standard buck switching regulator for I/O circuits, a linear controller for the GTL bus, and a linear regulator with built-in pass transistor for a clock generator.
On this basis, a hybrid power system for a PC mainboard is constructed. As compared with the conventional separate power systems on a PC mainboard, the hybrid power system of the present invention can save board area and reduce cost. Test results show this system has high precision and its synchronous switching regulator meets the specifications of Intel""s VRM8.4 design guidelines for Pentium III CPUs.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.